Polyalkylpiperidinyl-containing β-aminoacrylic ester derivatives

ABSTRACT

A polyalky-piperidinyl-containing β-aminoacrylic ester derivative represented by the formula I ##STR1## is useful in stabilizing plastic and paints against light, oxygen and heat.

The present invention relates to novel polyalkyl-piperidinyl-containingβ-aminoacrylic ester derivatives of the general formula I ##STR2## wheren is from 1 to 50,

R¹ and R² are identical or different and each is hydrogen, C₁ -C₆-alkyl, formyl, C₂ -C₆ -alkanoyl, C₁ -C₁₂ -alkoxy, C₅ -C₆ -cycloalkoxy,cyanomethyl, 2-hydroxyethyl, benzyl or a radical of the formula --CR³═CH--CO--OR⁴, and

R³ is hydrogen, C₁ -C₆ -alkyl or a radical of the formula --CO--OR⁴ and

R⁴ is C₁ -C₁₈ -alkyl, C₅ -C₈ -cycloalkyl, C₇ -C₁₈ -aralkyl, phenyl ortolyl,

A is C₂ -C₁₂ -alkylene, C₅ -C₈ -cycloalkylene, phenylene, biphenylene ora radical of the formula ##STR3## wherein m is 2 or 3, and when n=1

Y is hydrogen, C₁ -C₁₈ -alkyl, formyl, C₂ -C₁₈ -alkanoyl, C₇ -C₁₈-aralkyl or a group of the formula --CH═CH--CO--O--Z ,

B is a direct bond, and

Z is C₁ -C₁₈ -alkyl, C₅ -C₈ -cycloalkyl, C₇ -C₁₈ -aralkyl, phenyl, tolylor a radical of the formula --(CH₂ CH₂ O)_(p) H or -- CH(CH₃)CH₂ O!_(p)H, wherein p is from 1 to 30, and

when n>1

Y is hydrogen or a group of the formula--CH═CH--CO--O--X--O--CO--C.tbd.CH

B is a bridge member of the formula --CH═CH--CO--O--X--, in which case Zis bonded through the C--C double bond in B,

X is C₂ -C₁₈ -alkylene, C₅ -C₈ -cycloalkylene, phenylene, biphenylene ora group of the formula --(CH₂ CH₂ O)_(q) CH₂ CH₂ -- or -- CH(CH₃)CH₂O!_(q) CH(CH₃)CH₂ --, wherein q is from 1 to 30, and

Z is a group of the formula ##STR4##

The present invention further relates to organic material, in particularplastics and paints, stabilized against the action of light, oxygen andheat with the compounds I.

Organic material, in particular plastics and paints, is known to bedestroyed very rapidly, in particular by the action of light. Thisdestruction customarily takes the form of yellowing, discoloring,cracking or embrittlement of the material. Stabilizers are thereforeused to give satisfactory protection from destruction of organicmaterial by light, oxygen and heat.

For instance, EP-A-213 570 describes compounds in which twopolyalkylpiperidine groups are linked by a glycoluril bridge via anexocyclic nitrogen atom in the 4-position. These compounds can alsoexist in polymeric form. They are recommended for use as stabilizers fororganic material, in particular for plastics.

What is frequently unsatisfactory with these prior art agents is theirlow compatibility with plastics, the short duration of their protectiveeffect, their self-color, their volatility and their thermaldecomposition when being incorporated at elevated temperatures.

It is an object of the present invention to provide UV absorbers andstabilizers which provide more effective protection of organic material.

We have found that this object is achieved by thepolyalkylpiperidinyl-containing β-aminoacrylic ester derivatives Idefined at the beginning.

The variable n is preferably from 1 to 10, in particular 1.

R¹ and R.sup. 2 are each preferably hydrogen, methyl or a radical of theformula --CH═CH--CO--OR⁵, wherein R⁵ is C₁ -C₄ -alkyl. Here R¹ and R²are identical or different.

The variable A is preferably a group of the formula --(CH₂)_(k) --,wherein k is from 2 to 12, in particular from 2 to 8.

Very particular preference is give to β-aminoacrylic ester derivativesof the general formula Ia ##STR5## where R¹, R² and A are each asdefined above and R⁵ is C₁ -C₄ -alkyl.

Examples of suitable straight-chain or branched alkyl radicals for R¹ toR⁵, Y and Z, described as C₁ -C₄ --, C₁ -C₆ - and C₁ -C₁₈ -alkylradicals, are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,sec-butyl, tert-butyl, n-amyl, isoamyl, sec-amyl, tert-amyl, neopentyl,n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl,n-undecyl, n-dodecyl, n-tridecyl, isotridecyl, n-tetradecyl,n-pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl. Preference isgiven in general to lower alkyl radicals, in particular C₁ -C₄ -alkylradicals, especially methyl and ethyl.

As straight-chain or branched alkanoyl for R¹ and R² and for Y,described as C₂ -C₆ - and C₂ -C₁₈ -alkanoyl, it is possible to use inparticular acetyl, but also propionyl, butyryl, isobutyryl, pentanoyl,hexanoyl, heptanoyl, octanoyl, 2-ethylhexanoyl, decanoyl, dodecanoyl,tetradecanoyl, hexadecanoyl and octadecanoyl.

Suitable straight-chain or branched C₁ -C₁₂ -alkoxy groups for R¹ and R²are in particular C₆ -C₈ -alkoxy groups such as n-hexoxy, isohexoxy,n-heptoxy, isoheptoxy, n-octoxy, 2-ethylhexoxy and isooctoxy but alsomethoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy,tert-butoxy, n-pentoxy, n-nonoxy, n-decoxy, n-undecoxy and n-dodecoxy.

C₅ -C₆ -Cycloalkoxy groups for R¹ and R² are in particular cyclopentoxyand cyclohexoxy.

In a radical of the formula --CR³ ═CH--CO--OR⁴ for R¹ and R², R³ ispreferably hydrogen or C₁ -C₄ -alkoxycarbonyl, especiallymethoxycarbonyl or ethoxycarbonyl, and R⁴ is preferably C₁ -C₄ -alkyl,especially methyl or ethyl.

Suitable C₅ -C₈ -cycloalkyl radicals for R⁴ and Z are in particularcyclopentyl and cyclohexyl but also cycloheptyl, cyclooctyl,methylcyclopentyl, dimethylcyclopentyl, methylcyclohexyl,ethylcyclohexyl and dimethylcycohexyl.

Suitable C₇ -C₁₈ -aralkyl radicals for R⁴, Y and Z are for examplenaphthylmethyl, diphenylmethyl or methylbenzyl, but in particular C₇-C₁₈ -phenylalkyl such as 1-phenylethyl, 2-phenylethyl, 1-phenylpropyl,2-phenylpropyl, 3-phenylpropyl, 2-phenylprop-2-yl, 4-phenylbutyl,2,2-dimethyl-2-phenylethyl, 5-phenylamyl, 10-phenyldecyl,12-phenyldodecyl or especially benzyl.

Suitable tolyl is ortho-tolyl, meta-tolyl and in particular p-tolyl.

In a radical Z of the formula --(CH₂ CH₂ O )_(p) H or CH(CH₃)CH₂ O!_(p)H or in a group X of the formula --(CH₂ CH₂ O)_(q) CH₂ CH₂ -- or --CH(CH₃)CH₂ O!_(q) CH(CH₃)CH₂ --, p and q are each preferably from 1 to10, in particular from 1 to 5.

The C₂ C₁₂ -alkylene groups for the variable A, which constitutes abridge member between two polyalkylpiperidine groups for the link viatheir exocyclic nitrogen atoms in the 4-position, are embodied inparticular by polymethylene groups of the formula --(CH₂)_(k) --,wherein k is from 2 to 12, in particular from 2 to 8, ie. 1,2-ethylene,1,3-propylene, 1,4-butylene, pentamethylene, hexamethylene,heptamethylene, octamethylene, nonamethylene, decamethylene,undecamethylene and dodecamethylene. Of these, hexamethylene and1,2-ethylene are particularly preferred. But it is also possible toemploy branched C₂ -C₁₂ -alkylene groups, eg. --CH₂ CH(CH₃)CH₂ --, --CH₂C(CH₃)₂ CH₂ --, --CH₂ CH(C₂ H₅)-- or --CH₂ CH(CH₃)--.

Suitable C₅ -C₈ --cycloalkylene groups for A are in particularcyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene,methylcyclopentylene, dimethylcyclopentylene, methylcyclohexylene,dimethylcyclohexylene, ethylcyclohexylene and 1,3- or1,4-bismethylenecyclohexane.

Phenylene A is ortho- but in particular meta- and para-phenylene.Biphenylene is in particular 3,3'-, 4,4'- and 3,4'-biphenylene.

When n is 1, Y is preferably hydrogen or a group of the formula--CH═CH--CO--O--Z where Z is in particular C₁ -C₄ -alkyl. When n>1, Y ispreferably hydrogen.

The C₂ -C₁₈ -alkylene groups for the bridge member X which is present inthe case n>1 are embodied in particular by polymethylene groups of theformula --(CH₂)₁ --, wherein 1 is from 2 to 18, in particular from 2 to8, such as 1,2 -ethylene, 1,3-propylene, 1,4-butylene, pentamethylene,hexamethylene, heptamethylene, octamethylene, nonamethylene,decamethylene, undecamethylene, dodecamethylene, tetradecamethylene,hexadecamethylene and octadecamethylene. Of these, hexamethylene and1,2-ethylene are particularly preferred. But it is also possible to usebranched C₂ -C₁₈ -alkylene groups, eg. --CH₂ CH(CH₃)CH₂ --, --CH₂C(CH₃)₂ CH₂ --, --CH₂ CH(CH₃)--, --CH₂ CH(C₂ H₅)-- or --CH₂ C(CH₃)₂ CH₂CH₂ C(CH₃)₂ CH₂ --.

Suitable C₅ -C₈ -cycloalkylene groups for X are the same as for A.

The remarks concerning phenylene and biphenylene for A also apply to X.

In the case n>1, the end group is preferably a group of the formula##STR6##

The β-aminoacrylic ester derivatives I according to the invention areadvantageously preparable in the case n=1 by reactingpolyalkylpiperidine derivatives of the general formula II with propiolicesters of the general formula III ##STR7##

β-Aminoacrylic ester derivatives I in which n>1 are advantageouslysynthesized by polyaddition of compounds II to bispropiolic esters ofthe general formula IV. ##STR8##

This reaction can be carried out without any solvent or in an inertorganic solvent, in water or in mixtures thereof.

Suitable inert organic solvents for this reaction are for examplearomatics such as benzene, toluene, xylene, mesitylene, chlorobenzene,nitrobenzene or dichlorobenzene, ethers such as glycol dimethyl ether,glycol diethyl ether or methyl tert-butyl ether, etherols such as glycolmonomethyl ether, glycol monoethyl ether or glycol monobutyl ether,amides such as dimethylformamide or dimethylacetamide, esters such asbutyl acetate, ethyl acetate, methyl propionate, methyl benzoate orethyl benzoate, or alcohols such as methanol, ethanol, n-propanol,isopropanol, n-butanol, isobutanol, tert-butanol or glycol.

It is advantageous to employ elevated temperatures, for example withinthe range from 40° to 150° C., preferably within the range from 80° to100° C., and atmospheric pressure.

The compounds I according to the invention can be present in the form ofthe free bases or as salts. Suitable anions are derived for example frominorganic acids and in particular from organic carboxylic acids and alsoorganic sulfonic acids.

Suitable inorganic anions are for example chloride, bromide, sulfate,dicyanimide, methosulfate, tetrafluoroborate, phosphate and thiocyanate.

Suitable carboxylic acid anions are for example formate, acetate,propionate, hexanoate, cyclohexanoate, lactate, stearate,dodecylbenzoate, acrylate, methacrylate, citrate, malonate and succinateand also anions of polycarboxylic acids having up to 3000 COOH groups.

Sulfonic acid anions are for example benzenesulfonate and tosylate.

The compounds of the invention are highly suitable for stabilizingorganic material against the action of light, oxygen and heat. They alsoact as metal deactivators. They are added to the organic material to bestabilized in a concentration of from 0.01 to 5% by weight, preferablyfrom 0.02 to 2% by weight, based on the organic material, before, duringor after its preparation.

Organic material for the purposes of the present invention encompassesfor example cosmetic products such as creams and lotions, pharmaceuticalformulations such as pills and suppositories, photographic recordingmaterials, in particular photographic emulsions, and also intermediatesfor plastics and paints, but in particular the plastics and paintsthemselves.

The present invention also provides light- , oxygen- and heat-stabilizedorganic material, in particular plastics and paints, containing one ormore of the compounds I in the above-specified concentrations.

To blend in the compounds I of the present invention, especially intoplastics, it is possible to use any known apparatus and method formixing stabilizing or other additives into polymers.

The organic material stabilized by the compounds I of the presentinvention may contain other additives, for example antioxidants, lightstabilizers, metal deactivators, antistats, flame retardants, pigmentsand fillers.

Antioxidants and light stabilizers which may be added in addition to thecompounds of the present invention are for example compounds based onsterically hindered phenols or sulfur- or phosphorus-containingcostabilizers.

Such phenolic antioxidants are for example2,6-di-tert-butyl-4-methylphenol, n-octadecylβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane,1,3,5-tri-methyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-trisβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionylethyl!isocyanurate,1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate andpentaerythritol tetrakisβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate!.

As phosphorus-containing antioxidants it is possible to use for exampletris(nonylphenyl) phosphite, distearyl pentaerythritol diphosphite,tris(2,4-di-tert-butylphenyl)phosphite,tris(2-tert-butyl-4-methylphenyl) phosphite,bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite andtetrakis(2,4-di-tert-butylphenyl) 4,4'-bi-phenylene diphosphite.

As sulfur-containing antioxidants it is possible to use for exampledilauryl thiodipropionate, dimyristyl thiodipropionate, distearylthiodipropionate, pentaerythritol tetrakis(β-lauryl thiopropionate) andpentaerythritol tetrakis(β-hexyl thiopropionate).

Further antioxidants and light stabilizers which can be used togetherwith the compounds I of the present invention are for example2-(2'-hydroxyphenyl)benzotriazoles, 2-hydroxybenzophenones, aryl estersof hydroxybenzoic acids, α-cyanocinnamic acid derivatives,benzimidazolecarboxanilides, nickel compounds and oxalodianilides.

Suitable plastics for stabilization by the compounds I of the presentinvention are for example:

polymers of mono- and diolefins, eg. low or high density polyethylene,polypropylene, linear polybutene-1, polyisoprene, polybutadiene and alsocopolymers of mono- or diolefins or mixtures thereof;

copolymers of mono- or diolefins with other vinyl monomers, eg.ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylatecopolymers, ethylene-vinyl acetate copolymers or ethylene-acrylic acidcopolymers;

polystyrene;

copolymers of styrene or α-methylstyrene with dienes and/or acryloylderivatives, eg. styrene-butadiene, styrene-acrylonitrile (SAN),styrene-ethyl methacrylate, styrene-butadiene-ethyl acrylate,styrene-acrylonitrile-methyl acrylate, acrylonitrile-butadienestyrene(ABS) or methyl methacrylate-butadiene-styrene (MBS);

halogen-containing polymers, eg. polyvinyl chloride, polyvinyl fluoride,polyvinylidene fluoride and copolymers thereof;

polymers derived from α,β-unsaturated acids and derivatives thereof,such as polyacrylates, polymethacrylates, polyacrylamides andpolyacrylonitriles;

polymers derived from unsaturated alcohols and amines or from acryloylderivatives or acetals thereof, eg. polyvinyl alcohol and polyvinylacetate;

polyurethanes, polyamides, polyureas, polyesters, polycarbonates,polysulfones, polyether sulfones and polyether ketones.

The compounds I of the present invention can also be used forstabilizing coatings, eg. industrial coatings. They are especiallysuitable for baking finishes, in particular automotive coatings,preferably two-layer coatings.

The compounds I of the present invention can be added to the coatingcomposition in a solid or dissolved form. Their ready solubility incoating systems is of particular advantage here.

Preferably, the compounds I of the present invention are used forstabilizing polyamides and ABS and SAN polymers, in particular moldingmaterials prepared therefrom, and also surface coatings.

A further preferred field of use is the stabilization of polypropyleneand polyamide, in particular fibres thereof.

The compounds I of the present invention are highly compatible withcustomary types of plastic and readily soluble in conventional coatingsystems. In general, they have only minimal self-color, if any, arestable and nonvolatile at the customary plastic and paint processingtemperatures, and in particular confer a long period of protection onthe materials treated therewith.

The invention is further illustrated by the examples which follow. Thesynthesis conditions have not been optimized.

PREPARATION EXAMPLES EXAMPLE 1

78.8 g ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine wereintroduced in 300 ml of ethanol. 40 g of ethyl propiolate were addeddropwise with stirring at room temperature, and the temperature thenrose to 50° C. This was followed by heating at the boil for 1 h, coolingdown to 5° C. and the dropwise addition of 600 ml of water, whichbrought down white crystals. Filtration and drying left 112 g of thecompound of the formula ##STR9## as a colorless solid of melting point122°-129° C. The compound was further purified by recrystallization fromacetonitrile, and the melting point rose to 126°-130° C.

Analysis: Calculated C 69.1 H 10.6 N 9.5 Found C 68.8 H 10.6 N 9.4

EXAMPLE 2a

96 g of propiolic acid, 66.6 g of 1,6-hexanediol and 0.2 ml ofconcentrated sulfuric acid were heated in 600 ml of n-hexane under awater separator for 13 h, until the removal of water ceased. Two phaseswere obtained on cooling. The bottom phase was discharged into 1 l ofwater and stirred therein at room temperature for 1 h, which resulted inthe formation of a colorless solid precipitate. Filtration and dryingleft 115 g of the

bispropiolic ester of the formula ##STR10## of melting point 45°-47° C.

EXAMPLE 2b

To a solution of 19.7 g ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine in 50 mlof dimethylformamide was added dropwise at 50° C. a solution of 11.1 gof the bispropiolic ester of the Example 2a in 30 ml ofdimethylformamide. In the course of the addition the internaltemperature rose to 76° C. After 4 h at 70° C. the reaction solution wascooled back down to room temperature and 1.5 1 of water were addeddropwise with vigorous stirring. The resulting precipitate was filteredoff and dried under reduced pressure. This left 23.4 g of the oligomerof the formula ##STR11## of melting point 105° C. The average value forn was 7.1.

Analysis: Calculated C 70.1 H 10.5 N 9.1 Found C 68.8 H 10.5 N 9.2

EXAMPLE 3

To a solution of 78.8 g ofN,N'-bis-(2,2,6,6-tetramethyl-4-piperidinyl)hexamethylenediamine in 300ml of ethanol were added dropwise without cooling 80 g of ethylpropiolate over 1 h, in the course of which the temperature rose from20° C. to 58° C. After refluxing for 2 h the reaction mixture was cooleddown to 5° C., and the precipitate was filtered off, washed with 100 mlof cold ethanol and dried at 100° C. in a water jet vacuum. This gave132.5 g of the compound of the formula ##STR12## as a colorless solid ofmelting point 184°-187° C.

Analysis: Calculated C 67.1 H 9.5 N 7.1 Found C 67.0 H 9.6 N 7.2

We claim:
 1. Polyalkylpiperidinyl-containing β-aminoacrylic esterderivatives of the general formula I ##STR13## where n is from 1 to50,R¹ and R² are identical or different and each is hydrogen, C₁ -C₆-alkyl, formyl, C₂ C₆ -alkanoyl, C₁ -C₁₂ -alkoxy, C₅ -C₆ -cycloalkoxy,cyanomethyl, 2-hydroxyethyl, benzyl or a radical of the formula --CR³═CH--CO--OR⁴, and R³ is hydrogen, C₁ -C₆ -alkyl or a radical of theformula --CO--OR⁴ and R⁴ is C₁ -C₁₈ -alkyl, C₅ -C₈ -cycloalkyl, C₇ -C₁₈-aralkyl, phenyl or tolyl, A is C₂ -C₁₂ -alkylene, C₅ -C₈-cycloalkylene, phenylene, biphenylene or a radical of the formula##STR14## wherein m is 2 or 3, and when n=1 Y is hydrogen, C₁ -C₁₈-alkyl, formyl, C₂ -C₁₈ -alkanoyl, C₇ -C₁₈ -aralkyl or a group of theformula --CH═CH--CO--O--Z, B is a direct bond, and Z is C₁ -C₁₈ -alkyl,C₅ -C₈ -cycloalkyl, C₇ -C₁₈ -aralkyl , phenyl, tolyl or a radical of theformula --(CH₂ CH₂ O)_(p) H or -- CH(CH₃)CH₂ O!_(p) H, wherein p is from1 to 30, and when n>1 Y is hydrogen or a group of the formula--CH.tbd.CH--CO--O--X--O--CO--C.tbd.CH B is a bridge member of theformula --CH═CH--CO--O--X--, in which case Z is bonded through the C--Cdouble bond in B, X is C₂ -C₁₈ -alkylene, C₅ -C₈ -cycloalkylene,phenylene, biphenylene or a group of the formula --(CH₂ CH₂ O)_(q) CH₂CH₂ -- or -- CH(CH₃)CH₂ O!_(q) CH(CH₃)CH₂ --, wherein q is from 1 to 30,and Z is a group of the formula ##STR15##
 2. β-Aminoacrylic esterderivatives I as claimed in claim 1, wherein n is from 1 to
 10. 3.β-Aminoacrylic ester derivatives I as claimed in 1, wherein R¹ and R²are identical or different and each is hydrogen, methyl or a radical ofthe formula --CH═CH--CO--OR⁵, wherein R⁵ is C₁ -C₄ -alkyl. 4.β-Aminoacrylic ester derivatives I as claimed in claim 1 wherein A is agroup of the formula --(CH₂)_(k) --, wherein k is from 2 to
 12. 5.β-Aminoacrylic ester derivatives of the general formula Ia as claimed inclaim
 1. ##STR16## where R¹, R² and A are each as defined above and R⁵is C₁ -C₄ -alkyl.
 6. A light-, oxygen- and heat-stabilized organicmaterial containing from 0.01 to 5% by weight, based on the amount ofthe organic material, of one or more β-aminoacrylic ester derivatives Ias claimed in claim
 1. 7. A light-, oxygen- and heat-stabilized plasticor paint containing from 0.01 to 5% by weight, based on the amount ofthe plastic or paint, of one or more β-aminoacrylic ester derivatives Ias claimed in claim
 1. 8. A process for stabilizing organic materialagainst the action of light, oxygen and heat, which comprises using forthis purpose β-aminoacrylic ester derivatives I as claimed in claim 1.9. A process for stabilizing plastics and paints against the action oflight, oxygen and heat, which comprises using for this purposeβ-aminoacrylic ester derivatives I as claimed in claim 1.